Looking at the current BOM for the Express, most components can operate as low as -40C or -55C
the only things that seems close to your temp range (-20C) were of all things the sockets that hold the chips, which show a min operating range on -25C.
to be on the safe side, i'd add a c9 in there as well.
If you unplug your show, maybe plug it in at least 10min before the show comes on.